Basic Science of Wound Healing

Abstract

Patients with critical limb ischemia (CLI) present with ischemic rest pain or with tissue loss. Tissue loss, in its mildest presentation, includes focal ischemic ulceration or nonhealing wounds. Gangrene is the manifestation of severe chronic ischemia. Without revascularization, patients with CLI are at risk for limb loss and for potentially fatal complications from the progression of gangrene and the development of sepsis. The best patient outcomes are achieved when the diagnosis and appropriate treatment for CLI are not delayed. Simple noninvasive tests, such as measurement of ankle-to-brachial indices or toe Doppler pressures, take only minutes to provide sufficient information to confirm the diagnosis of peripheral artery disease (PAD) and to document the severity of limb ischemia. Subsequent diagnostic imaging studies, such as arteriography, magnetic resonance angiography, or ultrasound duplex scanning, provide the detailed information needed to plan revascularization therapy. Balloon angioplasty and stenting work best for focal segments of narrowing or short occlusions of the iliac arteries, but endovascular treatments yield progressively poorer results with longer and more distal lesions. Long segments of occlusion, especially those distal to the common femoral artery, are best treated with surgical bypass. Pharmacotherapy and adjunctive therapies, such as topical therapies or hyperbaric oxygen treatment, may have a limited role in patients in whom revascularization procedures have failed or for those in whom revascularization is not technically possible--particularly when amputation is the only alternative. Prostanoids are the best-studied class of drugs for such applications, but their use is still investigational in the United States. Though other medical approaches, such as use of other vasoactive agents, drugs that treat claudication, or gene-induced angiogenesis may prove useful, they do not yet have demonstrated roles in the treatment of patients with CLI.